Casual Sex
by liebdeinetraume
Summary: So this is basically about Eren and Levi having a strictly sex relationship that may grow into something more in a few chapters if I continue it. This is my first FanFic and if the response is positive, I will continue. The full summary is inside. :)
1. Chapter 1

This story was inspired by the song "Casual Sex" by My Darkest Days. I made my own spin-off of it, of course. I don't know why but that song really makes me want to write a FanFic about my OTP. Which is, of course, Eren and Levi.

Basically, if you haven't heard the song, the singer is having a strictly sex relationship with a woman. "We're single, but we're lovers". In this story, Eren and Levi have a strictly sex relationship to recover from the loss they have encountered and are blowing off steam and relieving stress. To me that's no fun, so we're gonna make it a little more fluffy. I'm going to try to keep them in character as much as I can.

This is my first FanFic, so the response I get from this story will let me know if I am a decent writer or no, and will decide if I continue this or not. If you don't like the pairing, and if you don't like gay sex, please see yourself to the digital door.

Disclaimer: I do not own Attack on Titan/Shingeki No Kyojin.

Its still so weird that the Corporal and I have been having sex regularly. I didn't think when I had first threw myself at him one drunken night after the female titan incident that he would welcome me with open arms. Sort of. More like welcome my dick. I can still recall those memories so vividly...

 _I was drunk off my ass. I had to wash away the pain of knowing that I killed my entire squad with any alcohol I could find. It was still so surreal that they were killed only a week ago. I had been avoiding the corporal as much as possible because I know he hates me for it. He always seems so distant and cold, uncaring. I know what others see. But what I see is so much worse. He has been fighting to keep a cold and calculating face for so long. I can see past his mask, though. Although, right now I cant really see anything in a straight line. My feet are wobbly and my vision has doubled._

 _I was walking down the corridor toward my cell to pass the fuck out when I saw the Corporal. I tried to hide but instead of stealthily ducking out of the way so he wouldn't see me; I fell flat on my face in the middle of the corridor. I swear to the goddesses, I have about as much grace as a fucking titan. I hear him stop in the hallway and could practically feel the glare he was giving me. "Oi, Yeager! What the fuck are you doing? I have been waiting by your damn cell for an hour to lock your ass up for bed." He stalks up to me radiating with irritation. "Uh sorry sir, I uh was just heading to my cell." I slur out this sentence, removing my face from the stone floor and getting up to salute my captain. I stumble a bit, and he hikes an eyebrow. "Have you been drinking, Yeager?" I gulp and reply with the affirmative. He sighs and promptly turns and drags me to the kitchen. He shoves me into the chair at the dining table and goes to the cupboard. I can't help but watch his ass as he moves to the sink. 'Damn, he has the nicest ass I have ever seen...' I watch tentatively as he fills a glass with water and walks over to the table. He sets the glass in front of me and sits across from me. "Drink that. You won't have a hangover in the morning, if you drink the whole glass." I look at him confusedly and drink the glass of water. This has to be the nicest he has ever been to me, I think. He grabs the glass and walks over to the sink to clean it out. When he's done, he turns and sees me staring at his ass. I avert my eyes quickly, turning a beet red._

 _He stands there for a minute, seemingly contemplating something, and walks over to me. "Oi, Yeager. Have you been watching my ass this whole time?" Impossibly, I turn even redder. I nod my head, at a loss for words on how to explain to my superior that yes, I am ogling your ass. He stands there for a second, then barks at me to get up. I follow him back to my cell and we both go into the dark room. I stand there a minute, thinking of how I can get this man to fuck me. He walks to my bed, gathering the chains, apparently unnoticed of my stopping. He finally notices that I've stopped and turns around to look at me. "Oi, brat, what are you waiting for, I'm fucking tired."_

 _In a spurt of confidence even I didn't know I had, I briskly walk to the captain and throw him against the wall and kiss him, hard. He goes rigid against my body in apparent shock and stares wide-eyed at me. At an attempt to get him to comply, I grind our clothed dicks together. This seems to break him out of whatever shock he was in and he growls, throwing me down on the bed. He climbs on top of me, gripping my hair pulling me into another kiss, this one much deeper. He grabs a fistful of my hair and yanks, causing me to yelp. Taking the advantage, he shoves his tongue inside my mouth. I tear his jacket off of his shoulders and throw it somewhere onto the floor, sure that he would nag at me about it later. In a blind fit of lust, I rip his button up shirt open, popping every button, tearing it off of his body, throwing it to the floor to join his jacket. He growls at the ripping of his shirt and says "you owe me a new damn shirt, brat." He moves to my neck, nipping and licking the whole way to my clavicle. I do not have a jacket on, so he removes my shirt in one swift movement, throwing it to the floor. He moves all the way down my torso, licking and biting the whole way down, earning lust filled whines from my throat. He moves down to my pants line, and tears open the fly. He looks up at me for confirmation to go ahead. I thrust my hips upwards, giving him the "hurry the fuck up" signal. He unbuttons my jeans with his teeth every so slowly, teasing me the whole while. When he finally gets the fly open, he strips me of my jeans and boxers in one swift movement. My pulsing erection twitches to the sudden change of temperature, making me groan. He licks a stripe from the base to the tip, earning a low groan of pleasure. He moves his mouth to the tip and licks the slit. I whine at him to stop teasing, then scream in pleasure when he engulfs my hard on with his hot cavern of a mouth. Goddesses, my hand has nothing against this man. I feel the tip of my dick hit the back of my throat and I can see stars. He has definitely done this before. I can hear him start to hum and the vibrations of his throat are moving through my cock up my spine causing me to scream in ecstasy. I can feel the hot coil in the pit of my stomach and gurgle out that I'm close. He abruptly stops and stands. I whine from the loss of contact when I look just in time to catch him strip himself the rest of the way. I can only stare at the God staring at me. "Jeez, brat, it looks like you're going to cum just looking at me." I can only stare in reply and he smirks. He gets between my legs again and engulfs me, once again. My back arches off the bed at the sudden warmth around my cock. I look down just in time to see him start to stroke himself and I groan from the lustfull sight. I get to near completion, once again, and when he hears my warning, he hollows out his cheeks, sucking harder and faster. I am a writhing mess of goo at this point. I give notice of my body wracking orgasm by arching my back so far off the bed its a wonder it didn't break in half, and silently scream out my orgasm. My vision has gone white with ecstasy and I can't think of a single moment in my life that I have ever felt that much fucking pleasure. I hear him swallow my orgasm and lean forward capturing me in a searing hot kiss. He pulls away and looks me in the eye. "Eren, I am going to fuck you into oblivion, now. I imagine you are still a virgin, so I will go easy, this time. I want to make one thing clear, however. This is only sex. We are relieving stress, and that is all this will ever be. If you cannot handle this, tell me now and I will leave. If you are content with how things will play out from now on, we can continue this. We are not going to be in a relationship, but we will be lovers. We may see others as we please. This is simply a side thing to blow off steam. Our relationship as superior and soldier will remain the same. Can you agree to this?" I am a little disappointed that he will never love me the way I always have, but any form of Levi I can get is enough for me. I nod my head in agreement, and he pulls me into another deep kiss._

 _His fingers find their way to my dick and pumps it a couple times to bring it back to hardness. He moves his finger to my puckered hole and circles the opening with his finger. I whine a little at the anticipation. He pulls his finger away and tells me to suck on his fingers. I pull three into his mouth and keep eye contact with him as I suck the shit out of his fingers, soaking them in my saliva. He growls and moves his finger back to my hole. I feel his other hand move to my dick as his finger pushes past the first ring of muscle. I scrunch my face up a little at the new discomfort of the foreign entity. He wiggles his finger around a little telling me to relax and breathe. As he is pumping my dick and soothing my discomfort, I relax around his finger enough for him to add another. He curls his fingers every which way appearing to be searching for something. As I am wondering what he could possibly be searching for inside my ass, he brushes his fingers against something inside me which causes me to screech and arch off the bed, making me see stars. "Ah! Oh fuck, Levi, right there! Fuck, do that again!" He smirks in victory and begins teasing that spot turning me into a pile of goo, again, within seconds. He adds the third finger and begins stretching me, preparing me for his manhood. He removes his fingers from my ass, and moves to spread his precum over his dick. He aligns himself to my hole and kisses me, pushing his dick through the first ring of muscles. I groan from the sudden sting of his large dick entering my ass. He continues in slowly all the way up to the hilt and stops. His eyes are scrunched as he concentrates on not pulling out and pounding into me, mercilessly. I grow accustomed to it shortly after he is fully in and move my hips in experimentation. "A-ah, you're good, Corporal, you can move." He groans as he moves his dick out almost all the way out, and slams back in, causing me to yell out. He sets the pace at a merciless rate and pounds into my bundle of nerves, once again. "Ah! Levi! Right there! Hit there again!" He realigns himself to hit that spot over and over again making me see white every time he hits it. I feel the familiar coil once again in the pit of my stomach. "C-corporal! I'm close!" He grunts and speeds up. My back arches once again and I scream out my release. He is right behind me, grunting out his release. He pulls out and lays next to me on the bed and we both come down from our high. He sits up and looks at me, and smirks. "Not bad, brat. Next time you know what to do." I blush and hide my face in the covers. "Get up, we need to change these sheets and get cleaned up, its disgusting."_

 _When we return from the showers, he leads me to the bed and chains me up. "Goodnight, brat." I smile up at him and whisper good night._

Its been 2 months since then, and nothing has changed, as he said. He has not treated me as a favorite and he has not confessed his love for me. We are strictly solder and superior, and on the side we are lovers without the love. Armin and Mikasa have not even the slightest of suspicions. We have had sex every weekend since that night. Every time, we shower, he chains me up, and leaves. Each night I am in hopes that he will change his mind and confess his love. Each night I am convinced he never will. I can only think that I am the luckiest man alive to even have the chance to touch the Corporal in such a way. I don't think of the others he has fucked, or any that he is fucking besides me. I don't think I can handle that pain. Then again, I am the soldier and he is the superior. Whatever he says goes. I can only keep the hope that one day he will fall in love with me and we will be together.

Alright guys, that's all I'm doing tonight. Depending on the response I get, if any, I may continue this. If you don't like it, don't comment. If you do like it, please let me know. If anyone has any suggestions, feel free to let me know. Thank you!


	2. Chapter 2

Hey guys, so I just got off work and have loads of energy so I'm gonna go ahead and write another chapter. I got a few good reviews so I will go ahead and continue this.

Holy fuck... Last night was rough. I never knew Corporal could be that fucking _flexible..._ I'm almost afraid of going and seeing him after the perimeter check outside the walls, tonight. I swear to the goddesses, if he tries to lift my legs any higher tonight I am going to become a human pretzel.

I walk into the dining hall to join Mikasa and the gang for breakfast when Hanji runs over to me. "Eren! Oh, there you are. The Commander has asked me to grab you so he can brief you on your outing tonight." I sigh a relief that she hasn't come to grab me for another experiment. I nod to her and head to the Commanders office so I can be briefed for the mission. I knock on the door and go in when I hear the muffled "come in".

Erwin looks up and sees me and sets his pencil down. "Ah, Eren, there you are. I see Hanji has found you with no problem. Now, tonight you and Corporal Levi are going to be venturing outside the walls to do a perimeter check. You will be accompanied by a few of your comrades, and it should be a fairly quick sweep. We are only wanting to make sure there are no titans wandering too close to camp. You have heard of these outings, I'm sure, but we have decided to let you go on this one since it will be fairly simple." He pauses and looks at me to make sure I am following along. "You will be leaving around 21:00 tonight. Meet up with Corporal Levi and your friends in the training yard ten minutes before you are scheduled to leave. Do you have any questions?" I shake my head and salute the Commander and am dismissed.

I head to the dining hall again and am greeted by Armin and Jean. "Hey, horseface." Jean looks up at me and punches my shoulder as I greet Armin. Mikasa and the rest of the gang have joined us and are all joking around when I can feel someone staring at me. I look around to see who is staring when I meet steel gray eyes. 'Why does he look so pissed off?' I wonder. He's glaring daggers at me and Jean and averts his gaze. Weird. I turn back around when I hear someone calling me. "EREN! Are you listening?!" Mikasa looks worried, as always. "Huh? Oh, no. Sorry I was just dozing off. I'm a little tired. What were you saying?" She sighs and repeats. "I was asking if you're going on the perimeter check tonight. Me, Armin and Jean will be going along with Corporal Levi." Well, now I know who will be joining us. "Oh! Yeah, I spoke to the Commander about that before I came to breakfast." She nods and continues eating.

Breakfast is over and we're all heading out to the training field when I feel a hand grip my wrist and pull me into a cleaning supply closet. "What the fuck, what are you doing?" Instead of hearing Corporal's voice like I had figured, I hear Jean's voice. "I've been wanting to do this for a while now." Before I can ask what the fuck he is talking about, I feel him push me up against the wall and his lips are on mine. I freeze and stand there motionless out of shock when he grabs my clothed dick. I moan and he shoves his tongue in my mouth, mapping out the inside of my mouth. When he starts to undo my pants, the door is yanked open and there is a very angry Levi standing there glaring at us. "I don't know why you two are fucking in the cleaning supply room, but you need to get the fuck out and get to training, now." His voice is dripping venom and we scramble out of the cleaning supply closet. When we get to the training field, the others raise their eyebrows at our disheveled appearances. Reiner whistles at us and immediately stops when he receives a very menacing glare from Mikasa, who turns her glare to Jean. The Corporal joins us on the training field and begins the session.

It is now 20:00 and I am exhausted. The Corporal pushed Jean and I extremely hard, today. No doubt from the cleaning supply incident. I trudge my way to my cell so I can out of my training clothes when I run into Corporal Levi.

"Oi, brat, watch where you're going!" He spits out at me. I apologize and go to move around him when he steps in my way. "Sir?" I ask, tentatively. "What the fuck makes you think you can fuck other people in supply closets, hm?" I gape at him, completely confused. Didn't he say we were free to see other people...? "Um, sir, I'm sorry but I didn't initiate that encounter with Jean. And anyway, I thought you said we were free to see other people?" I'm growing angry at this point. He narrows his eyes and gives me a menacing glare. "Watch your tone, brat. I changed my mind; you are mine and mine alone." I stare at this man incredulously. "Wait, so we are going to have a strictly sex relationship that has absolutely no feelings toward each other, and we can only have this relationship with each other. That's complete bullshit! I can't just tie myself down to one person who feels absolutely nothing toward me when there is another man who might actually feel something for me!" I'm shouting at him and he looks absolutely pissed. "What, you think that horsefaced bastard actually cares about you? Come on, Eren, the way you two fight, he just wants to fuck you and run. He doesn't give a damn about you." These words sink in and my spine is splashed with ice. The words hurt more than they were probably meant to and I push past him to my room, slamming the door shut. He doesn't follow.

20:45 rolls around and I head out to the training field to meet my squad for the perimeter check. My eyes are still a little red from what Corporal Levi said earlier and Mikasa has already picked up on it. "Eren? What's wrong? Did Jean hurt you? I'll kill that bastard!" She turns to find Jean and I grab her arm. "No, it wasn't Jean. Don't worry about it, Mikasa, I'll be fine." She puts her fists down reluctantly and faces forward as we all salute the Corporal as he arrives. He looks us all over, eyes lingering a second longer on me and Jean, when he tells us to get our horses.

We head out of the gates toward the forest right after we get the horses. We ride maybe 5 kilometers out when we spot a titan. The corporal orders us to change to 3DMG and we lift ourselves into the trees, after tying our horses up to the nearest tree. Mikasa goes after the titan and in one swift movement, brings it down. We continue through the outskirts of the forest when we are suddenly surrounded by titans. The Corporal shouts for us to go higher to avoid them when one grabs a hold of Jean. "JEAN!" I turn to help him when Levi shoots past us and takes down the titan, releasing Jean of the titans hold. It seems his maneuvering gear wasn't damaged, and he makes it up the rest of the way to join us. He gets to our branch and slumps down against the tree trunk to regain his breath. I move over to him to make sure he's okay when he just grins at me and starts laughing. I smack his arm and yell at him for laughing when he almost just fucking died. I turn just in time to see the Corporal watching us from the corner of his eye, before averting his gaze.

We manage to take out the titans that are below with the help of mostly Mikasa and the Corporal. (Seriously, those two make an awesome fucking team.) We make it back to headquarters without a scratch. Well, except Jean, he has a bruise from the titan that grabbed him. But he doesn't count.

When we've all eaten dinner, we head back to our bunks. Jean hasn't attempted anything further than what happened in the supply closet, and I haven't asked him about it. Everything has basically stayed the same. Except Levi. He seems extremely irritable. He's avoided me all night up to this point, but he has to chain me up for the night so he has to speak to me eventually. Not that I care. He was a dick earlier, so if he thinks he's getting fucked tonight he's wrong.

I make it to my room, and sure enough, he's sitting in the chair by the cell door. He see's me coming and stands up to follow me to the bed. I sit on the edge of the bed, awaiting for him to say something, when he sits beside me. He seems to be struggling with his words, so I keep quiet until he can find the right words to begin.

"Look, Eren, I didn't mean what I said earlier. I don't know what the fuck it is you do to me, but for some reason I can't just keep you as my soldier. I've never felt these feelings of jealousy and feelings for other people besides the occasional friendship, but I'm experiencing all of it for the first time with you. When we first started this, I didn't feel these feelings. But each night I spend with you, I feel myself fall more in love with you. Goddesses know why, you're a whiny brat and you annoy the shit out of me sometimes. But there are moments when you're just so passionate it's admirable. You're eyes glow a brighter green and you just glow with determination. And goddesses, you're sexy as fuck when you're done getting a pounding from me, with your bright red cheeks and disheveled hair. Basically, what I'm trying to tell you, is that I suck at mushy shit and I love you." I can't help but stare at him wide eyed as he finishes his statement. I know how awkward it is for him to be so open with his emotions, so I'm glad he at least tried. I smile at him and lean forward, capturing his mouth in a kiss. I pull away and look into his eyes. "I've been in love with you since I first met you. You were my childhood hero, and still am. Honestly, I was a little upset when you said you wanted a sex only relationship, but I figured I would take all I could get. I had hoped you would come around, eventually." I smiled victoriously at him as he rolls his eyes and pins me to the bed. "Oh-ho, brat, getting cocky, aren't we?" I smirk and reply "I can get cocky as soon as we get naked." He chuckles at the corny pun and pulls me into a deep kiss. This kiss feels much different from our previously shared kisses, however. Normally our kisses and touches feel like wildfire, but this time it feels like molten magma moving deep inside.

Levi removes my shirt and his own and sets them neatly on the floor. Much unlike all of our previous encounters. He straddles my waist and moves his hands to my nipples. He pinches one of them and starts rolling it around between his forefinger and this thumb, making me moan in pleasure, squirming to find some contact. He smirks into the kiss and moves his mouth to my neck, sucking and biting in the junction of my neck. "Fucking brat, my marks will be gone by morning. No matter, we will just have to make more." I smile at the ceiling and groan as he moves his mouth to my nipple, taking the bud between his teeth, as his fingers play with the other. He moves his hand down to my clothed erection and palms me through the cloth. I moan loudly as he slips his hand down my pants and grips my erection. He removes his hand from my erection and moves to take my pants off. I tug on the hem of his jeans and he chuckles before he slips out of his own jeans, while removing mine as well, placing them on the floor. Before he can move another muscle, I flip him on his back and maneuver my way between his legs causing him to grunt in surprise. "Brat, what are you- _oh..."_ I hear him moan out the rest of his sentence as I take the entirety of his length into my mouth. His dick hits the back of my throat and I thank the goddesses I don't have any gag reflexes. I start to bob my head up and down, humming to send vibrations down his dick. I am determined to make this man vocal tonight. I succeed as I hollow out my cheeks and go faster, as he moans out my name, very loudly, I might add. "E-eren, fuck, I-I'm close!" I increase my speed and feel him tighten beneath me and hear him scream out his release as I swallow his load. I smile and make my way back to his mouth. He yanks me down to his mouth and tongue fucks my mouth. "Damn brat, taking me by surprise. You're gonna pay for that." He smiles wickedly as he grabs my wrists and locks them in the chains. He tightens the chains so my arms are above my head and I can't move them. I look at him in slight fear and he smirks at me. My legs are lifted and folded up to my shoulders as he disappears from sight. I wonder momentarily what he could be doing when I feel something wet and warm enter my ass. "Oh, fuck! Corporal, please, more!" He pauses slightly then speeds up. All I can do is moan like a whore and struggle against my restraints. He stops and lifts his head and shoves his fingers in my face, ordering me to suck. Not a problem there, for I'm already fucking drooling. When his fingers are wet enough, he shoves two in. My back arches off the bed as the fingers are added into my hole. He moves his mouth to my dick once again and starts sucking as he finger fucks me. He knows just how to turn me into a pile of goo. I don't even feel the third finger enter, I only feel him remove his finger and remove his mouth and whine from the loss. I gasp when I feel him align his dick with my ass and shove in to the hilt. He pauses for only a moment as he pulls out and slams back in, already knowing where to aim. He throws my legs over his shoulders to get a deeper angle, and pounds into me mercilessly. I'm screaming in ecstasy when he leans down and captures my lips in a heated kiss. "You're mine, brat. You belong to me. Only I will ever be able to see you unravel like this." Its a fucking wonder he can talk in such a complete sentence. It's not fair, really. "Ah- y-yes, Corporal, o-only yours! Ah! Fuck! Harder!" He smirks and increases his speed, wrapping his hand around my dick to add to the stimulation. I cry out my warning. "Come for me, Eren." I cant help but scream out my release when I hear his command. He thrusts in twice more before he shudders to a stop, moaning out my name as he releases.

We collapse beside each other, completely spent. That has to be the best sex we've ever had. I turn to look at him and snuggle into his chest. He's never let me snuggle into him, but I feel his arms go around me protectively. "I love you.." I whisper to him. He sighs contentedly. "I love you too, brat. Now get some sleep, we'll shower in the morning." Sleep is exactly what hits me as he says his last word.

Alright guys, that's it. I don't think there's really any other chapters to add to this one. Let me know what you think. If you think I should add more, I can figure something out. I'm thinking of writing a modern AU one after this if I can get some inspiration. Dunno. Leave reviews, let me know what you think. Thanks for reading!


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